[CentOS] 32bit versus 64bit memory usage?

Tue Aug 29 07:17:53 UTC 2006
Morten Torstensen <morten at mortent.org>

> Christian Nygaard wrote:
>> I'm planning for new Centos 4 computers using the 64bit distribution 
>> and is wondering
>> if there is a difference on how much RAM memory you should use on a 
>> 32bit versus
>> 64bit operating system?

Yes. Several low-limits are higher on 64-bit than on 32-bit, like minimum for 
Gnome install is 128MB on 32-bit and 256MB on 64-bit. I assume you would have 
more memory than that anyway. 64-bit will use more memory, how much depends. If 
you add 20% to what you need on 32-bit you should generally be safe. What kind 
of system are you considering 64-bit on?

Feizhou wrote:
> there is no difference in how much RAM memory you should use but if you 
> are going to get a box with more than 1GB of RAM (I think it is 1G...) 
> using AMD's (note Intel: EMT64 cpus don't count) cpus will give you 
> better memory performance.

You really like broad, general statements with your personal opinion, right? :)

AMD's on-chip memory controller gives it lower latency, no matter how much 
memory you have installed. Memory DIMM mix for Dual Channel can give bandwidht 
improvements, but both for Intel and AMD architectures. Yes, there are minute 
differences in how EMT64 and AMD64 chips handles page tables and addressable 
memory but for all practical intents and purposes they are the same.

-- 

//Morten Torstensen
//Email: morten at mortent.org
//IM: Cartoon at jabber.no morten.torstensen at gmail.com

And if it turns out that there is a God, I don't believe that he is evil.
The worst that can be said is that he's an underachiever.